| Seamless carbon steel pipe | A solid steel billet is heated, pierced, and rolled or drawn into a hollow tube. Finishing may include heat treatment, sizing, and inspection. | ASTM A106/A106M; ASTM A53/A53M Type S; API Specification 5L | Has no longitudinal weld seam. Available in multiple grades and schedules; suitability depends on the specified grade, dimensions, and service conditions. | Oil and gas systems, refineries, power plants, and other pressure or process piping services. |
| ERW pipe | Flat steel strip is formed into a cylinder, and its edges are joined by electric resistance welding. The weld is typically inspected and finished in line. | ASTM A53/A53M Type E; API Specification 5L | Longitudinally welded pipe produced from coil or strip. Production efficiency and available dimensions depend on the mill and specification. | Water and gas distribution, structural uses, and specified line-pipe services. |
| Longitudinal SAW pipe | Steel plate is formed into a pipe shape, then the longitudinal joint is welded using a submerged arc welding process. | API Specification 5L; ASTM A671 or ASTM A672, as applicable to the ordered service | Large-diameter pipe can be made from plate. The applicable specification defines requirements such as grade, testing, and service conditions. | Transmission pipelines, water infrastructure, and pressure-service projects where the selected specification is suitable. |
| Spiral SAW pipe | Steel strip is helically formed into a cylinder and joined along a spiral seam by submerged arc welding. | API Specification 5L and project-specific requirements, where applicable | Manufactured from coiled strip; diameter and wall thickness ranges depend on the production line and order specification. | Water transmission, infrastructure, and selected pipeline projects. |
| Low-temperature carbon steel pipe | Produced as seamless or welded pipe, with grade-specific material controls and testing. Heat treatment and impact testing depend on the specification and grade. | ASTM A333/A333M | Specified for low-temperature service; required impact-test temperatures and acceptance criteria are grade- and order-dependent. | Refrigeration and process piping, and other services requiring material performance at low temperatures. |
| Pressure-service welded pipe | Made by a specified welding route, such as electric-fusion welding, with inspection and testing requirements set by the applicable specification. | ASTM A671/A671M; ASTM A672/A672M | These specifications cover electric-fusion-welded steel pipe for defined pressure-service conditions; material class and testing requirements vary by designation. | Pressure piping in power, industrial, and process facilities when the specified class and service conditions are appropriate. |
| General-purpose carbon steel pipe | Can be manufactured as seamless or welded pipe, depending on the type and requirements ordered. | ASTM A53/A53M | Specification covers black and hot-dipped, zinc-coated welded and seamless steel pipe in the specified grades and types. | Mechanical and pressure applications, as well as ordinary uses in steam, water, gas, and air lines, subject to specification limits. |
| Line pipe | Seamless or welded production routes may be used. Manufacturing controls, inspection, and testing are specified by the ordered product level and grade. | API Specification 5L | Designed for pipeline transportation applications. Grade, dimensions, manufacturing route, and supplementary requirements are selected for the project. | Oil, gas, and other pipeline transportation systems, subject to the applicable design code and service requirements. |